In general, a library apparatus such as a magnetic tape library apparatus includes a storage unit for storing a plurality of cartridges each accommodating a storage medium such as magnetic tape, a drive unit for carrying out recording and reproduction of data from the storage medium in the cartridge, and an accessor robot (accessor) for transferring the cartridge between the storage unit and the drive unit.
In response to a cartridge access request from a host apparatus, the accessor moves to the storage unit, searches for a desired cartridge, grasps the cartridge using a hand mechanism, and transfers it to the drive unit. After completion of the processing, the cartridge is removed from the processing section by the hand mechanism of the accessor and conveyed to the storage unit for storage.
The cartridge may, for example, be a magnetic tape cartridge 10 having magnetic tape as the storage medium, as shown in FIG. 10. Moreover, the tape cartridge 10 may include a leader block 10a attached to the tip portion of the magnetic tape for pulling out a magnetic tape (not shown).
A cartridge 10 (FIG. 11) is inserted/removed from a magnetic tape drive unit (MTU) 5a by a hand mechanism 7a of an accessor 7 while being guided by right and left guides 5a-1. The magnetic tape is drawn out of the cartridge 10 into the MTU 5a by the leader block 10a.
If the leader block is improperly seated within the cartridge, the library apparatus may experience difficulty in handling the cartridge and/or processing data from the cartridge. See, e.g. the two-dot chain line in FIG. 10.
By manner of illustration, FIG. 12 shows a cartridge 10 being taken out from the MTU 5a and grasped by the hand mechanism 7a. As shown, the cartridge is inclined with respect to the moving direction of the hand mechanism 7a. Notably, the inclination makes it difficult to insert the cartridge 10 into a given cell in the storage unit. Moreover, inclination of the cartridge may cause difficulty in inserting the cartridge 10 into the MTU 5a.
A cartridge which can not be handled due to an improperly seated leader block or the like is treated as a defective cartridge. In a conventional system, defective cartridges are placed by the accessor in a pocket for storage within the library apparatus. Moreover, the intervention of a skilled technician is required in order to access the defective cartridges stored within the pocket.
To ensure reliable entry/exit of the cartridge 10, a conventional library apparatus has been provided with a mechanism for delivery and reception of the cartridge. This mechanism is provided between the MTU 5a and the hand mechanism 7a in the accessor 7. Recently, however, in order to reduce the overall size of the library apparatus, it has been desirable to design a library apparatus which does not use this delivering and receiving mechanism. In such a configuration, the accessor 7 has been designed to directly insert the cartridge 10 into the MTU 5a as shown in FIGS. 11 and 12. Direct entry of the cartridge by the accessor into the MTU 5a makes a size-reduction of the hand mechanism 7a essential. Accordingly, not only the hand mechanism 7a but also the accessor 7 have undergone a size-reduction.
However, the size-reduction of the hand mechanism 7a reduces the contact area in which the hand mechanism 7a grasps the cartridge 10. This reduction may cause difficulty in grasping the cartridge 10. In particular, there is a possibility that the hand mechanism 7a may be unable to grasp the cartridge 10 in a correct posture, making it difficult to insert the cartridge 10 into the MTU 5a (see FIG. 11). Moreover, the cartridge will be judged defective if the hand mechanism 7a experiences difficulty in handling the cartridge; whereupon it will be transported to the pocket.
The present invention has been developed with a view to eliminating this problem, and it is therefore an object of this invention to provide a library apparatus with a simple and compact arrangement which is capable of immediately and forcibly discharging defective cartridges outside of the library apparatus.